The present invention relates to a metal laminate gasket with a surface pressure adjusting ring for adjusting surface pressure around a hole to be sealed.
In a metal laminate gasket, it is conventional to provide a bead and/or a wire ring around a hole to be sealed. When the gasket is tightened, the bead and the wire ring are compressed, so that the hole is sealed therearound.
Automobile engines have been developed to provide high power with light weight. In order to satisfy these demands, an aluminum alloy has been used for a cylinder head. The cylinder head made of the aluminum alloy is good for the cylinder head. However, since the aluminum alloy is not so strong against mechanical strength, in case wire rings are used for sealing around cylinder bores of the engine, the cylinder head made of the aluminum alloy may be damaged. Namely, when the cylinder head is tightened, dents of the wire rings are liable to be formed on the cylinder head, through which gas may leak from the cylinder bore.
Even if the wire rings are not formed around the cylinder bores, in case an engine is formed of an aluminum alloy, the engine, especially areas around the cylinder bores, may be easily deformed when high tightening pressure is applied thereto. Therefore, the engine made of the aluminum alloy must be tightened carefully not to deform the same.
Accordingly, it is desirous to provide a gasket having means to properly control surface pressure applied to the areas around the cylinder bores when the engine is tightened.
Accordingly, one object of the present invention is to provide a metal laminate gasket, which can easily regulate surface pressure around a hole to be sealed.
Another object of the invention is to provide a metal laminate gasket as stated above, which can provide a plurality of sealing portions around a hole to be sealed to prevent concentration of sealing pressure at one portion.
A further object of the invention is to provide a metal laminate gasket as stated above, which can securely seal around a hole of the engine without causing creep relaxation of sealing means.
Further objects and advantages of the invention will be apparent from the following description of the invention.